We present ALMA mosaic observations at 1.3. mm (223 GHz) of the Fomalhaut system with a sensitivity of 14 mu Jy/beam. These observations provide the first millimeter map of the continuum dust emission from the complete outer debris disk with uniform sensitivity, enabling the first conclusive detection of apocenter glow. We adopt an MCMC modeling approach that accounts for the eccentric orbital parameters of a collection of particles within the disk. The outer belt is radially confined with an inner edge of 136.3 +/- 0.9. au and width of 13.5 +/- 1.8. au. We determine a best-fit eccentricity of 0.12 +/- 0.01. Assuming a size distribution power-law index of q. =. 3.46 +/- 0.09, we constrain the dust absorptivity power-law index a to be 0.9 <beta <. 1.5. The geometry of the disk is robustly constrained with inclination 65 degrees. 6 +/- 0 degrees. 3, position angle 337 degrees 9 +/- 0 degrees.3, and argument of periastron 22 degrees.5 +/- 4 degrees. 3. Our observations do not confirm any of the azimuthal features found in previous imaging studies of the disk with Hubble Space Telescope, SCUBA, and ALMA. However, we cannot rule out structures. 10 au in size or that only affect smaller grains. The central star is clearly detected with a flux density of 0.75 +/- 0.02. mJy, significantly lower than predicted by current photospheric models. We discuss the implications of these observations for the directly imaged Fomalhaut b and the inner dust belt detected at infrared wavelengths.

Recent Atacama Large Millimeter/submillimeter Array observations present mounting evidence for the presence of exocometary gas released within Kuiper Belt analogs around nearby main-sequence stars. This represents a unique opportunity to study their ice reservoir at the younger ages when volatile delivery to planets is most likely to occur. We here present the detection of CO J=2-1 emission colocated with dust emission from the cometary belt in the 440 Myr old Fomalhaut system. Through spectrospatial filtering, we achieve a 5.4s detection and determine that the ring's sky-projected rotation axis matches that of the star. The CO mass derived (0.65-42) x10(-7) M-circle plus is the lowest of any circumstellar disk detected to date and must be of exocometary origin. Using a steady-state model, we estimate the CO+ CO2 mass fraction of exocomets around Fomalhaut to be between 4.6% and 76%, consistent with solar system comets and the two other belts known to host exocometary gas. This is the first indication of a similarity in cometary compositions across planetary systems that may be linked to their formation scenario and is consistent with direct interstellar medium inheritance. In addition, we find tentative evidence that(49 +/- 27)% of the detected flux originates from a region near the eccentric belt's pericenter. If confirmed, the latter may be explained through a recent impact event or CO pericenter glow due to exocometary release within a steady-state collisional cascade. In the latter scenario, we show how the azimuthal dependence of the CO release rate leads to asymmetries in gas observations of eccentric exocometary belts.